Python 实现的PageRank算法,纯粹使用python原生模块,没有使用numpy、scipy。这个程序实现还比较原始,可优化的地方较多。
#-*- coding:utf-8 -*-
import random
N = 8 #八个网页
d = 0.85 #阻尼因子为0.85
delt = 0.00001 #迭代控制变量
#两个矩阵相乘
def matrix_multi(A,B):
result = [[0]*len(B[0]) for i in range(len(A))]
for i in range(len(A)):
for j in range(len(B[0])):
for k in range(len(B)):
result[i][j] += A[i][k]*B[k][j]
return result
#矩阵A的每个元素都乘以n
def matrix_multiN(n,A):
result = [[1]*len(A[0]) for i in range(len(A))]
for i in range(len(A)):
for j in range(len(A[0])):
result[i][j] = n*A[i][j]
return result
#两个矩阵相加
def matrix_add(A,B):
if len(A[0])!=len(B[0]) and len(A)!=len(B):
return
result = [[0]*len(A[0]) for i in range(len(A))]
for i in range(len(A)):
for j in range(len(A[0])):
result[i][j] = A[i][j]+B[i][j]
return result
def pageRank(A):
e = []
for i in range(N):
e.append(1)
norm = 100
New_P = []
for i in range(N):
New_P.append([random.random()])